A variety of implantable devices can be used to augment or replace natural biological functions. For example, cochlear implants can be used to provide a sense of hearing to deaf or severely hard of hearing patients. Cochlear implants typically include an exterior portion and an implant portion. The implanted portion includes a processor, antenna, and electrode array that is implanted within or near the cochlea or auditory nerve. The electrode array is electrically driven by the implanted processor and antenna. The antenna receives external signals and electrical power. These signals and power are used by the processor selectively simulate the cochlea using the electrode array. The implanted processor and antenna are typically implanted under the patient's skin and connected to the electrode by a multi-wire lead.
Stabilizing implanted devices in the biological tissues can be challenging. Biological systems are typically dynamic with a wide range of forces that are exerted on the implant. For example, preventing the implanted processor and antenna in a cochlear implant from shifting after implantation can be important for a number of reasons. If the implanted processor and antenna shift after implantation, then wires in the lead can be damaged or the electrode array can be displaced. Additionally, shifting of the processor and antenna can cause tissue trauma and associated biological responses.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.